title: Left ventricular volumes and systolic function after long-term right ventricular pacing may be predicted by paced QRS duration, but not pacing site.
abstract: BACKGROUND
  Long-term right ventricular apical (RVA) pacing causes adverse left ventricular (LV) remodelling and clinical outcomes.
  
  
  METHODS
  Forty-one patients (19 men, mean age 70.9±14.2, 23 right ventricular septal and 18 RVA pacing) underwent pacemaker implantation for atrioventricular block. LV volumes and left ventricular ejection fraction (LVEF) were assessed by echocardiography 39.3±17.2 months after implantation. Predictors of left ventricular systolic volume (LVESV), left ventricular diastolic volume (LVEDV) and LVEF were analysed.
  
  
  RESULTS
  No difference was found between RVA pacing and right ventricular septal pacing groups in LVESV (40.6±22.6 vs 33±14.4ml; p=0.199), LVEDV (88.2±31.2 vs 73.7±23.9ml; p=0.102) and LVEF (56.1±8.6 vs 56±6.6%; p=0.996). With multivariate stepwise regression, only pQRSd and renal impairment independently predicted LVESV (β=0.522, 95% CI: 0.242-0.802; p=0.001 and β=40.3, 95% CI: 17.6-62.9; p=0.001 respectively), LVEDV (β=0.786, 95% CI: 0.338-1.235; p=0.001 and β=42.8, 95% CI: 6.6-79; p=0.022 respectively) and LVEF (β=-0.161, 95% CI: -0.283 to -0.04; p=0.011 and β=-14.8, 95% CI: -24.6 to -5.0; p=0.004 respectively).
  
  
  CONCLUSIONS
  pQRSd and renal impairment, but not pacing site or baseline LVEF, may be predictors for LV volumes and systolic function after long-term RV pacing. pQRSd may be target for pacing site optimisation.
authors.affiliation: Princess Margaret Hospital, Hong Kong. Electronic address: ngaiyinchan@yahoo.com.hk.
authors.forename: Ngai-Yin
authors.initials: NY
authors.lastname: Chan
authors.affiliation: Princess Margaret Hospital, Hong Kong.
authors.forename: Ho-Chuen
authors.initials: HC
authors.lastname: Yuen
authors.affiliation: Princess Margaret Hospital, Hong Kong.
authors.forename: Chi-Chung
authors.initials: CC
authors.lastname: Choy
authors.affiliation: Princess Margaret Hospital, Hong Kong.
authors.forename: Ngai-Shing
authors.initials: NS
authors.lastname: Mok
authors.affiliation: Princess Margaret Hospital, Hong Kong.
authors.forename: Ping-Tim
authors.initials: PT
authors.lastname: Tsui
authors.affiliation: Princess Margaret Hospital, Hong Kong.
authors.forename: Chun-Leung
authors.initials: CL
authors.lastname: Lau
authors.affiliation: Princess Margaret Hospital, Hong Kong.
authors.forename: Ying-Keung
authors.initials: YK
authors.lastname: Lo
authors.affiliation: Princess Margaret Hospital, Hong Kong.
authors.forename: Pui-Shan
authors.initials: PS
authors.lastname: Chu
authors.affiliation: Princess Margaret Hospital, Hong Kong.
authors.forename: Hoi-Fan
authors.initials: HF
authors.lastname: Chow
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002304:Cardiac Pacing, Artificial; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D012189:Retrospective Studies; D013318:Stroke Volume; D016277:Ventricular Function, Left; D020257:Ventricular Remodeling
keywords: Cardiac pacing; Electrocardiography; Left ventricular remodelling; Left ventricular volumes; Right ventricular apical pacing; Right ventricular septal pacing